A novel method for depth profiling and imaging of semiconductor devices using capacitive coupling voltage contrast

A scanning electron microscope was used in the voltage contrast mode to examine the relationship between dynamic secondary electron emission from passivated devices and buried structure depth. A primary electron beam energy of 500 eV was used. Depth measurement was performed on floating structures with an average error of 6.59%, 4.93% standard deviation, over a depth range of 0.04–0.76 μm. Further, a method of producing capacitive coupling voltage contast (CCVC) images of unbiased devices was developed, having a spatial resolution of better than 1 μm micron through passivation. A modified version of the Gorlich model for CCVC decay is presented to explain the experimental results [S. Gorlich, K. D. Herrmann, and E. Kubalek, in Proceedings of the Microcircuit Engineering 84 Conference (Academic, London, 1985)].